Six weeks after the tragedy, she cried as she held on to her replacement leg.

"This is like seeing my child walk for the first time again," her mom said on video, just before Haslet-Davis stood up on her own. "It's pretty emotional and it's pretty exciting. But she's a star. She's amazing."

Of the experience, Haslet-Davis said, "It feels really good to stand up right now. I haven't stood up in a really long time. I almost forgot what it felt like. It reminds me of dancing and I just so desperately want that again. And I'm so close. It feels really good."

Another scene shows her in rehabilitation six months after the bombings.

"I think I'm farther than I thought I'd be in six months," she said. "I made a strong point to not dwell on the people [who] did this. I insist on being called a survivor, not a victim. A victim … means I somehow belong to somebody or I'm suffering because of him. I'm not suffering. I'm thriving."

Shortly after the incident, she told the Associated Press, "I absolutely want to dance again and I also want to run the marathon next year. I will crawl across the finish line – literally crawl, if it means I finish it."